1. Field of the Invention
The present invention relates to helical-scanning signal recording apparatuses and methods that form tracks inclined with respect to a magnetic tape, and in particular, to a signal recording apparatus and method for recording signals on a magnetic tape by using a plurality of recording modes for different recording densities.
2. Description of the Related Art
A conventional helical-scanning recording apparatus is known in which a magnetic tape as a recording medium is run wound around a rotary drum, and recording tracks inclined with respect to the travelling direction of the magnetic tape are formed using magnetic heads mounted on the rotary drum so that audio signals, video signals, etc., are recorded.
The helical-scanning recording apparatus includes, in general, at least a pair of recording magnetic heads having different azimuths (hereinafter referred to as a "positive azimuth recording magnetic head" and a "negative azimuth recording magnetic head"). The helical-scanning recording apparatus alternately forms positive azimuth recording tracks and negative azimuth recording tracks on the magnetic tape at a predetermined track pitch by alternately using the positive and negative azimuth recording magnetic heads to perform recording.
In addition, recently, a recording apparatus has been proposed that detects errors by performing a playback of signals recorded by a recording magnetic head, and records the same signals again when having detected an error in the recorded signals so that the reliability of the recorded signals is enhanced.
In this type of recording apparatus, the positive azimuth recording head and the negative azimuth recording head are fixed on the same head base mounted on a rotary drum so as to be adjacent to each other. The recording apparatus checks reproduction of the recorded signals in a semi-cyclic revolution of the rotary drum in which the positive and negative azimuth recording magnetic heads are not in contact with the magnetic tape.
The recording apparatus can prevent a problem in that a large amount of recording current flows in the reproducing system because the recording apparatus does not simultaneously perform recording and reproduction check. In the recording apparatus, the pair of positive and negative azimuth recording magnetic heads is provided on the rotary drum so that they are adjacent to each other. This arrangement prevents a recording position shift in units of revolutions of the rotary drum, which causes a problem in a case where the pair of positive and negative azimuth recording magnetic heads are provided so as to be opposed to each other, whereby recording tracks can be formed at an accurate pitch.
In recording apparatuses for recording signals on a magnetic tape, it has recently been studied that a surface recording density is increased by reducing a track pitch for recording tracks formed on the magnetic tape in order to enable a large amount of recording for coping with an increased amount of information to be processed. Also, it is required that the recording apparatuses have so-called "compatibility" in which recording using a small track pitch and recording using a conventional track pitch can be performed.
Among the recording apparatuses, a type of recording apparatus, which has a pair of positive and negative azimuth recording magnetic heads provided on the rotary head so as to be opposed to each other, easily changes a track pitch for recording tracks formed on the magnetic tape by changing the feeding speed of the magnetic tape. Thus, the above-described compatibility between the small track pitch and the conventional track pitch can be easily obtained.
Conversely, in a type of recording apparatus having a pair of positive and negative azimuth recording magnetic heads provided on the rotary head so as to be adjacent to each other, the width of each recording track formed on the magnetic tape is determined by a track-widthwise distance between the positive and negative azimuth recording magnetic heads, that is, a head position difference. Accordingly, in this type of recording apparatus, it is difficult to obtain the above-described compatibility between the small track pitch and the conventional track pitch. This complicates the apparatus structure and the apparatus control in that, for example, a plurality of recording magnetic heads is provided on a rotary drum so that different head position differences are formed, and the recording magnetic heads are selectively used for recording.